For example, a welding system is known in which in order to seal (weld) a continuous laminate for each unit of disposable pants, a pair of ultrasonic horns and a pair of anvils are provided (WO05/080065A1).
In this conventional art, continuous webs are reversed with a reverse roll, and an anvil roll is provided that has a pair of anvils which can make contact with the webs in both upstream and downstream sides with respect to the reverse roll. With the ultrasonic horn corresponding to each of the anvils, seal processing is performed on the webs before and after the webs pass the reverse roll.